1. Field of Invention
The present invention relates to implementing links formed by more than two interfaces in a communication network.
2. Related Art
The patent application EP 01400826.2, filed in the name of THOMSON multimedia on Mar. 30, 2001 defines the behavior of devices acting as interfaces between clusters of devices over a wireless link. According to the embodiment of this patent application, each link is formed by two interface devices, called ‘wireless devices’, connected to their respective cluster. In the embodiment of the cited patent application, a cluster is formed around a wired IEEE 1394 bus, and mainly links comprising two interfaces are discussed. Wireless devices as described in the embodiment of the patent application cited above implement part of the Hiperlan 2 Data Link Control (DLC) layer, and functions of the Hiperlan 2 IEEE 1394 Service Specific Control Sublayer (SSCS).
The present invention concerns the problem of implementing links formed by more than two interface devices.
Bridges between two IEEE 1394 busses are currently being standardized by IEEE. The corresponding draft standard is:
(1) IEEE P1394.1 “Draft Standard for High Performance Serial Bus Bridges” Draft 0.14, Dec. 21, 2000.
ETSI is also working on the standardization of an IEEE 1394 Service Specific Convergence Sublayer and on an IEEE 1394 Bridge Specific Functions sublayer:
(2) ‘Broadband Radio Access Networks (BRAN); HIPERLAN Type 2; Packet based convergence layer; Part 3: IEEE 1394 Service Specific Convergence Sublayer (SSCS), version 1.2.1A of January 2001. This document addresses the transport of IEEE 1394 traffic between Hiperlan 2 devices.
(3) Broadband Radio Access Networks (BRAN) HIPERLAN Type 2 Technical Specification; Packet based Convergence Layer, Part 4: IEEE 1394 Bridge Specific Functions sub-layer for restricted topology, version 1.1.1 (July 2001).
It is to be noted that documents (2) and (3) describe architectures in which the wireless medium is represented as an individual, separate bus compared to the busses interconnected by the bridge, each individual bus being identified by a unique bus identifier, and each node of the network being defined by the identifier of its local bus and a own identifier, called physical identifier. In other words, the bridges described by these two documents are not transparent.
The present invention on the other hand concerns transparent bridges, each node of the network believing it is on a same, single bus with all other nodes of the network.